Processes for remediation of a contaminated material

ABSTRACT

Methods to remediate a contaminated material are provided. In one embodiment, a biocatalyst that digests hydrocarbon contaminants is activated with a nutrient and the activated biocatalyst is combined with the contaminated material and water to form a mixture. The mixture is incubated for a period of time, and the level of contaminant in the mixture is determined to ascertain whether to incubate further, add additional biocatalyst mix, or provide the remediated material for further processing. In one embodiment, the remediated material is provided for reuse or recycling with a second material, such as a construction aggregate. The method is particularly suited for remediation of drill cuttings, mine tailings, hydrocarbon-contaminated soil, and the like.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/009,075, filed Jun. 6, 2014 and of U.S. Provisional Application No.62/121,732, filed Feb. 27, 2015, both of which are incorporated byreference herein in their entirety.

TECHNICAL FIELD

The subject matter described herein relates to processes for remediatinga contaminated material using biologically active agents to yield aremediated material that can be reused and/or recycled.

BACKGROUND

The clean-up or removal of contaminants from various settings, includingsoil, sand, and ground and surface water, remains an on-going need.Hydrocarbon spills, chemical spills and industrial processes result inunwanted compounds becoming associated with settings wherein thecompound is considered a contaminant. Of particular problem arecontaminants from offshore and onshore oil and gas exploration andproduction. Drilling wells to extract oil and gas produces drillcuttings that are solid oil and gas drilling waste materialscontaminated with hydrocarbon. Other contamination problems areaccidental chemical, e.g., hydrocarbon, spills, from offshore rigs,ships, trains, and factories, where inadvertent mishaps result indischarge of a chemical such as a hydrocarbon compound at a site, suchas soil, sand or water, where it is viewed as a contaminant. Thereremains a need for processes to remove contaminants from materials, andpreferably to remediate the contaminated material in a process that doesnot yield a waste stream that requires further processing or disposal ata waste site, and preferably provides a remediated material that can bereused or recycled.

BRIEF SUMMARY

The following aspects and embodiments thereof described and illustratedbelow are meant to be exemplary and illustrative, not limiting in scope.

In one aspect, a method to remediate a contaminated material isprovided. The method comprises activating a biocatalyst that digestshydrocarbon contaminants with a nutrient, to provide an activatedbiocatalyst; introducing in the presence of water the activatedbiocatalyst to a contaminated material to form a mixture; incubating themixture for a period of time; determining a property of the mixture; anddetermining a level of contaminant in the mixture.

In one embodiment, activating may comprise activating for between 5-24hours, or until the nutrient is more than 50% consumed by thebiocatalyst, or until carbon dioxide level in effluent gas associatedwith the biocatalyst and nutrient is above a threshold level. In anotherembodiment, activating may comprise activating until the biocatalyst isaggressively digesting the nutrients and suitable for transition to thehydrocarbon contaminated material. Remaining or undigested nutrientsremain in the mixture to support the transition and the decomposition ofthe contaminant (e.g., target hydrocarbons). Elevated localized carbondioxide levels are observed in effluent gas associated with the processof hydrocarbon decay.

In another embodiment, a property of the mixture is determined duringthe method, where the property can be pH, dissolved oxygen content,viscosity, or some combination of two or three of these properties.

In yet another embodiment, the method further comprises adjusting pH,adjusting dissolved oxygen content or adjusting viscosity of themixture. In one embodiment, a pH level of less than 3 or a pH level ofgreater than 11 triggers adding an additional amount of the aqueousmixture to the mixture.

In one embodiment, during the period of incubation time the mixture ismixed periodically. In another embodiment, the period of incubation timeis from 6-8 hours. In other embodiments, the period of incubation isdetermined based on ambient conditions and altitude.

In still another embodiment, determining a level of contaminantcomprises testing for a hydrocarbon contaminant level.

In one embodiment, the method comprises adding an additional amount ofactivated biocatalyst when a contaminant level is above a thresholdamount to form an adjusted mixture.

In yet another embodiment, the method comprises mixing the adjustedmixture, incubating the adjusted mixture and testing the adjustedmixture for hydrocarbon contaminant level.

In another embodiment, incubating is performed at ambient temperature orat a preselected temperature.

In still another embodiment, activating further comprises activating thebiocatalyst in the presence of a surfactant.

In one embodiment, the nutrient is a sugar or is a compound thatprovides nitrogen, potassium, or phosphates. In another embodiment, thenutrient is a food source, which may be a sugar or another food orenergy source.

In another embodiment, the biocatalyst comprises bacterialmicroorganisms, intracellular enzymes, or extracellular enzymes.

In exemplary embodiments, the contaminated material is drill cuttings,soil, mine tailings, water contaminated with oil, or water contaminatedwith an organic solvent, such as mineral oil or a synthetic oil.

In one embodiment, the contaminated material is drill cuttings and themethod further comprises pretreating the drill cuttings with activatedbiocatalyst prior to introducing the activated biocatalyst to thepretreated, contaminated material to form a mixture.

In another aspect, a method to remediate a contaminated material isprovided. The method comprises providing a biocatalyst; instructing toactivate the biocatalyst by incubation with a nutrient to provide anactivated biocatalyst; and instructing that the activated biocatalyst beadmixed with water and a contaminated material to remediate thecontaminated material.

In one embodiment, instructing to activate comprises instructing toactivate for between 5-24 hours, or wherein instructing to activatecomprises instructing to activate until the nutrient is more than 50%consumed by the biocatalyst, or wherein instructing to activatecomprises instructing to activate until carbon dioxide level in effluentgas associated with the biocatalyst and nutrient is above a thresholdlevel. In another embodiment, instructing to activate comprisesinstructing to activate is performed under conditions to achieve anactivated biocatalyst with an amount of nutrient in excess of thatneeded to activate the biocatalyst.

In another embodiment, instructing that the activated biocatalyst beadmixed with water and a contaminated material forms a mixture, and themethod further comprises instructing to determine a property of themixture wherein the property is selected from pH, dissolved oxygencontent, and viscosity.

In yet another embodiment, the method further comprises instructing thatone or more of pH, dissolved oxygen content or viscosity of the mixturebe adjusted.

In still another embodiment, instructing comprises informing that a pHlevel of less than 3 or a pH level of greater than 11 triggers adding anadditional amount of the water to the mixture.

In one embodiment, instructing to activate the biocatalyst by incubationwith a nutrient comprises instructing to activate the biocatalyst byincubation with a nutrient for an incubation period during which mixingoccurs periodically.

In another embodiment, the method further comprises instructing todetermine a level of contaminant.

In still another embodiment, the method further comprises instructing toadd an additional amount of activated biocatalyst when a contaminantlevel is above a threshold amount, to form an adjusted mixture comprisedof the contaminated material, activated biocatalyst, additional amountof activated biocatalyst and contaminated material.

In yet another embodiment, the method comprises instructing to mix theadjusted mixture, to incubate the adjusted mixture and test the adjustedmixture for hydrocarbon contaminant level. In one embodiment,instructing to activate the biocatalyst by incubation with a nutrientcomprises instructing to incubate at ambient temperature.

In yet another aspect, a method to remediate and recycle a contaminatedmaterial is provided. The method comprises providing a biocatalyst and anutrient that when mixed form an activated biocatalyst; mixing theactivated biocatalyst with water and a contaminated material to form amixture; incubating the mixture for a period of time; testing themixture to ascertain contaminant level; processing the mixture to form aremediated material; and processing the remediated material with asecond material to form a recycled product.

In one embodiment, the second material is a material suitable for use asa flexible base material for construction.

In another embodiment, the material suitable for construction is anaggregate comprised of gravel, sand or crushed stone.

In yet another embodiment, the second material is used to form a baselayer of a paved surface or use used to form a paved surface, where thepaved surface is selected from a road, a driveway, a parking lot or asidewalk.

In one embodiment the contaminated material is drill cuttings and themethod further comprises pretreating the drill cuttings by spraying or“washing” the hydrocarbon contaminated material with activatedbiocatalyst prior to mixing the activated biocatalyst with water and thepretreated, contaminated material to form a mixture.

Additional embodiments of the present methods will be apparent from thefollowing description, drawings, examples, and claims. As can beappreciated from the foregoing and following description, each and everyfeature described herein, and each and every combination of two or moreof such features, is included within the scope of the present disclosureprovided that the features included in such a combination are notmutually inconsistent. In addition, any feature or combination offeatures may be specifically excluded from any embodiment of the presentinvention. Additional aspects and advantages of the present methods areset forth in the following description and claims, particularly whenconsidered in conjunction with the accompanying examples and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates steps of one embodiment of a process for remediatinga contaminated material;

FIG. 2 is a flow diagram that shows steps of another embodiment of aprocess for remediating drill cuttings, such as hydrocarbon-contaminateddrill cuttings associated with a borehole from an oil or gas well; and

FIG. 3 is a flow diagram that shows steps of another embodiment of aprocess for remediating contaminated soil.

DETAILED DESCRIPTION I. Definitions

Various aspects now will be described more fully hereinafter. Suchaspects may, however, be embodied in many different forms and should notbe construed as limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey its scope to those skilled in theart.

Where a range of values is provided, it is intended that eachintervening value between the upper and lower limit of that range andany other stated or intervening value in that stated range isencompassed within the disclosure. For example, if a range of 1 μm to 8μm is stated, it is intended that 2 μn, 3 μm, 4 μm, 5 μm, 6 μm, and 7 μmare also explicitly disclosed, as well as the range of values greaterthan or equal to 1 μm and the range of values less than or equal to 8p.m.

As used in this specification, the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to an “agent” includes a single agent aswell as two or more of the same or different agents.

II. Process for Remediation

The process described herein remediates a contaminated material using anatural catalyst, also referred to as a biological catalyst orbiocatalyst, which has activity to decompose, degrade, consume or digestan organic or inorganic contaminant. In the process, the biocatalyst isactivated and mixed with the contaminated material. The process isparticularly useful for remediation of hydrocarbon-contaminatedmaterials, such as soil, water, drill cuttings and mine tailings. Aswill be described in the embodiments below, the remediated material canbe reused or recycled, and the process remediates the material withoutgenerating a waste stream or effluent that requires disposal orclean-up.

A. General Process

With initial reference to FIG. 1, a first embodiment of the processcomprises preparing an activated biocatalyst 10. In one embodiment, thebiocatalyst is activated by combining the biocatalyst, a nutrient and,optionally, water in a suitable container. Water is added to themixture, for example, if the biocatalyst and/or nutrient is/are in dryform. If either of these components is provided as a solution orsuspension in water, addition of water may not be necessary. Thecomponents remain in combination for a period of time sufficient tocreate the activated biocatalyst. The period of time needed to activatethe biocatalyst will depend on the microbes and/or enzymes in thebiocatalyst, the nutrient selected for use, temperature, volume, andother factors. In some cases, the biocatalyst is activated in about 1-30minutes or about 1-60 minutes or about 5-60 minutes upon combinationwith a nutrient, and in other situations the biocatalyst and thenutrient require an activation time of between about 1-24 hours, betweenabout 5-24 hours, between about 5-18 hours, or between about 8-15 hours.

As mentioned above, the biocatalyst has activity to decompose, degrade,consume or digest an organic or inorganic contaminant. Biocatalystssuitable for use in the process include enzymes and microorganisms, suchas bacteria, yeast and fungi. The biocatalyst can be a mixture ofenzymes and micro-organisms and in one embodiment is comprised ofbacterial microorganisms, extracellular enzymes and intracellularenzymes. In one embodiment, the contaminant is a hydrocarbon, and thebiocatalyst comprises a bacteria. Bacteria known to feed exclusively onhydrocarbons, and in the feeding process to degrade the hydrocarbon, areknown as obligate hydrocarbonoclastic bacteria, and are found in marineenvironments and in soil (Yakimov, M. et al., Current Opinion inBiotechnology, 18(3):257 (2007)). For example, Acinetobacter sp. wasfound to be capable of utilizing n-alkanes of chain length C₁₀-C₄₀ as asole source of carbon (Yakimov, supra). Bacterial genera, namely,Gordonia, Brevibacterium, Aeromicrobium, Dietzia, Burkholderia, andMycobacterium isolated from petroleum contaminated soil were identifiedas organisms for hydrocarbon degradation, as well as Sphingomonas beingcapable of degradation of poly-aromatic hydrocarbons (Yakimov, supra).

Biocatalysis in the form of enzymes, yeast and fungi capable ofdegrading or participating in the degradation process of hydrocarbonsare also known in the art. Fungal genera, namely, Amorphoteca,Neosartorya, Talaromyces, and Graphium and yeast genera, namely,Candida, Yarrowia, and Pichia isolated from petroleum-contaminated soilare organisms for hydrocarbon degradation (Yakimov, supra). A group ofterrestrial fungi, namely, Aspergillus, Cephalosporium, and Pencilliumare reported to degrade crude oil hydrocarbons (Yakimov, supra). Theyeast species, namely, Candida lipolytica, Rhodotorula mucilaginosa,Geotrichum sp, and Trichosporon mucoides isolated from contaminatedwater were noted to degrade petroleum compounds (Yakimov, supra).Enzymes produced by microorganisms that are involved in biodegradataionof hydrocarbons include soluble monooxygenases, produced fromMethylococcus, Methylosinus, Methylocystis, Methylomonas, andMethylocella use C₁-C₈ alkanes, alkenes and cycloalkanes as substrates.Particulate methane monooxygenases are produced from the microorganismsMethylobacter, Methylococcus, and Methylocystis and use C₁-C₅(halogenated) alkanes and cycloalkanes as substrates. The enzymes AlkBrelated alkane hydroxylases are produced from the microorganismsPseudomonas, Burkholderia, Rhodococcus, and Mycobacterium and use C₅-C₁₆alkanes, fatty acids, alkyl benzenes, cycloalkanes as substrates.(Yakimov, supra).

Hydrocarbons differ in their susceptibility to microbial attack. Thesusceptibility of hydrocarbons to microbial degradation can be generallyranked as follows: linear alkanes>branched alkanes>smallaromatics>cyclic alkanes. Petroleum hydrocarbons can be divided intofour classes: the saturates, the aromatics, the asphaltenes (phenols,fatty acids, ketones, esters, and porphyrins), and the resins(pyridines, quinolines, carbazoles, sulfoxides, and amides). In oneembodiment, the processes described herein are contemplated for use inremediation of any one of or any combination of hydrocarbons, selectedfrom linear alkanes, branched alkanes, small aromatics, and cyclicalkanes.

With continuing reference to FIG. 1, the biocatalyst is activated bycombining it with a nutrient. In one embodiment, the nutrient can be asugar, such as a monosaccharide or a disaccharide or an oligosaccharide.Examples include sucrose, glucose, fructose, galactose, maltose, andlactose. In another embodiment, the nutrient is compound or compositionthat provides one or more of nitrogen, potassium, and/or phosphate. Oneexample is a fertilizer that provides all three of nitrogen, potassiumand phosphate. Other examples are compounds that contain, and donate,nitrogen, such as urea, nitropropane, ammonium nitrate and anhydrousammonia, and compounds that contain phosphate, such as phosphoric acid.

In one embodiment, the biocatalyst is activated in the presence of asurfactant. In another embodiment, a surfactant is added to thecontaminated material. A surfactant acts to lower the surface tensionbetween the aqueous phase of the mixture and the hydrocarboncontaminant, and can bring the components of the mixture into moreintimate contact for enhanced remediation. Zwitterionic, anionic andcationic surfactants may be suitable, depending on the contaminant andother components of the mixture. Examples include ammonium laurylsulfate, sodium lauryl sulfate, sodium laureth sulfate, dioctyl sodiumsulfosuccinate, alkyl ether phosphates, lecithin, benzalkonium chloride,dioctadecyldimetylammonium bromide. Non-ionic surfactants may also besuitable and include fatty alcohols, polyoxyethylene glycol alkylethers, glycosides, polyoxyethylene glycol octylphenol ethers,poloxamers, polysorbates, and sorbitan alkyl esters.

Activation of the biocatalyst can be ascertained based on knowledge ofthe biocatalyst properties and its requirements for activation, in termsof time, temperature and nutrition. Activation of the biocatalyst canalso be ascertained by an analytical approach, for example, by measuringcarbon dioxide production in the head space of the container in whichthe biocatalyst and nutrient are combined, where an initial increase inCO₂ production may be observed as the microorganisms in the biocatalystbegin consumption of the nutrient and CO₂ production may plateau as themicroorganisms reach a steady state consumption of nutrient indicatingactivation. When CO₂ content in a space associated with the biocatalystis above a certain level or plateaus at a certain level this serves asan indicator that the biocatalyst is activated. The consumption ofnutrient by the biocatalyst can also be measured to ascertainactivation, for example, by measuring nitrogen, sugar, or phosphoruscontent and observing an initial decrease in the content of one of thesecompounds. When a certain percentage of the compound, such as 50%, 60%,65% or more than 50%, 60%, or 65%, is consumed or depleted this is anindication that the biocatalyst is activated. In one embodiment,activation of the biocatalyst is conducted for a fixed period of timethat can range from less than one hour (e.g., 5 minutes to 59 minutes)or can be for between 1-24 hours, 5-24 hours, 8-24 hours, 10-20 hours,12-20 hours, or 18-24 hours.

The activated biocatalyst is mixed with the contaminated material, asindicated at 12 in FIG. 1. In one embodiment, the contaminated materialand activated biocatalyst are combined in situ, intending that theactivated biocatalyst is introduced at the site of contamination. Inanother embodiment, the contaminated material and activated biocatalystare combined ex situ of the contaminated site and/or of the location ofthe contaminated material. The contaminated material and activatedbiocatalyst are introduced in a suitable container, such as a drillcuttings box, a recycling waste skip or a boat rubbish skip or wasteskip. Water is introduced concurrently or sequentially with thecontaminated material and activated biocatalyst into the container, toform a mixture.

FIG. 1 also illustrates an optional pretreatment step that can beconducted for certain contaminated materials, and in one embodiment theoptional pretreatment step is undertaken when the contaminated materialis a hydrocarbon contaminate, such as cuttings from oil/gas drillingsites. For materials contaminated with hydrocarbons, the contaminatedmaterial can be optionally pretreated, as indicated at 11 in FIG. 1,with an activated biocatalyst (and/or an optional surfactant) prior tomixing the activated biocatalyst with the contaminated material (asdiscussed in the preceding paragraph with respect to 12 in FIG. 1.). Theoptional pre-treatment, sometimes referred to as a “wash” or “spraypre-treatment” of the contaminated material with activated biocatalysttypically involves contacting the contaminated material with theactivated biocatalyst such as by spraying the activated biocatalyst ontothe contaminated material (e.g., drill cuttings). As a skilled artisanunderstands, when drill cuttings are remediated, the conventionalpractice is to transfer the cuttings from the rig to a shaker. From theshaker, the fluid is recycled back to the rig and the cuttings aretransferred to a dryer and/or a centrifuge to further separate thecuttings from the drilling fluids. The present process contemplates theuse of a second set of shakers, the drying shakers, that follows the rigshakers and before other drying or remediation apparatus, to allowcontacting the drill cuttings when on the drying shaker, such as byspraying the activated biocatalyst onto the cuttings. The activatedbiocatalyst sprayed across the drying shaker washes the hydrocarbonsfrom the exterior of the hydrocarbon contaminated material and thismixture drains to a separate holding tank where it is allowed toseparate into the respective oil and water phases. The activatedbiocatalyst is recycled to the drying shaker for reuse in the process,utilized in the slurry process, or is disposed of, while the oil baseddrilling fluids from the shaker is recycled to the drilling operation atthe rig, and the cuttings, now pretreated with activated biocatalyst,are transferred to a container for further treatment (e.g., thepretreated cuttings are used in step 12, described above, by mixing thepretreated contaminated material with activated biocatalyst.

The mixture is incubated, 14, for a period of time. Typically, theincubation occurs at ambient temperature in which the container isplaced, although it is contemplated that the container could be warmedor cooled as needed for the incubation period. During incubation themixture can be mixed and/or tested (assayed). In one embodiment, themixture is mixed periodically. In another embodiment, a sample of themixture is taken periodically to determine a property of the mixture inorder to gauge decomposition of the contaminant, health/activity of thebiocatalyst, etc. The mixture can be tested to determine it pH level,its oxygen content or viscosity, for example. In some situations, a pHlevel of less than 3 or a pH level of greater than 11 serves as anindicator for making an adjustment to the mixture to bring the pH of themixture between about 3 and about 11. An adjustment to the pH can bedone by adding additional water, a buffer, or other chemical to adjustthe pH, thus forming an ‘adjusted mixture.’ The oxygen content of themixture can be altered by adding additional water or by mixing, thusforming an ‘adjusted mixture.’ The viscosity of the mixture can beadjusted by adding additional water, contaminated material or athickener, to form an ‘adjusted mixture.’

The mixture, or adjusted mixture, is incubated for a period of time. Theperiod of incubation time will vary depending on a number of factorsidentifiable to a skilled artisan, including type of contaminant, extentof contamination, biocatalyst used in the process, and temperature. Inone embodiment, the incubation time is for between about 2-48 hours, orbetween about 2-24 hours, or between about 4-20 hours, or between about4-18 hours, or between about 6-12 hours or between about 6-8 hours.

During or after the incubation time the mixture or adjusted mixture istested to determine the concentration or level of contaminant, 16. Wherethe contaminant is a hydrocarbon, a sample of the mixture or adjustedmixture is taken from the container and tested for concentration of thehydrocarbon, using known analytical techniques such as retort, gaschromatography, high pressure liquid chromatography, atomic absorption,spectrophotometry, and the like. Incubation continues until a desiredreduction in contaminant level is achieved, with adjustments to themixture and testing of contaminant level repeated as needed.

Once the contaminant level in the mixture is at or below a desiredlevel, the mixture is considered to be a mixture containing a remediatedmaterial. The mixture with the remediated material is then returned tothe original contamination site, reused or recycled, 18.

In another aspect, a process to remediate a contaminated materialcomprises providing a biocatalyst alone or in conjunction with anutrient for the biocatalyst. The biocatalyst is provided along withinstructions to (i) activate the biocatalyst by incubation with anutrient to provide an activated biocatalyst; and (ii) admix theactivated biocatalyst with water and a contaminated material toremediate the contaminated material. The instructions that accompany thebiocatalyst can also include instructions to activate the biocatalystfor a period of time (such as any of the time periods specified above),to mix the activated biocatalyst with the contaminated material to forma mixture, and to adjust the properties of the mixture as needed. Theinstructions can also include instructions to determine a level ofcontaminant.

B. Drill Cuttings, Mine Tailings

A working embodiment of the process described above is set forth in FIG.2, where the process is utilized to remediate hydrocarbon-contaminateddrill cuttings or mine tailings. Mine tailings are materials left overafter extraction of valuable minerals from ore. The mine tailings aredistinct from “waste rock” that is moved and discarded along with soiland organic matter as miners dig down to access the underlying ore. Thesize and composition of the mine tailings varies depending on the miningmethod. For example, in hardrock metal mining the ore is usually crushedand then processed, resulting in fine particles that may also containchemicals used for mineral extraction. Disposal of mine tailings isusually the single biggest environmental concern facing a hardrock metalmine. Toxic chemicals used to extract the valuable materials from theore, such as cyanide used in gold mining, remain in the tailings at theend of the process, and may leach out into ground water. The processesdescribed herein are contemplated for use in remediating mine tailings.

When drilling oil and gas wells into subterranean formations below theearth's surface particles of the formation drilled through, known asdrill cuttings, are formed by the drilling process. These cuttings varyin size from sand size to pebble size (grain size classes andterminology is known in the art, for example, by the Wentworth sizeclass, where sands to pepples range in grain size from 0.0625 mm to 16mm) and can carry petroleum hydrocarbons from a hydrocarbon-baseddrilling mud used to drill the well, from petroleum hydrocarbonsnaturally occurring in the formations that were drilled through, or fromother sources. The result is that the drill cuttings recovered at theearth's surface carry, either internally or on their surface or both,petroleum hydrocarbons. The processes described herein are contemplatedfor use in remediating drill cuttings.

In remediating drill cuttings or mine tailings, the process reduces thetotal hydrocarbon or petroleum hydrocarbon content to an environmentallyfriendly or regulatory acceptable level for return to the original siteof contamination or reuse or recycling. Environmentally friendly levelrefers to any federal, state or local requirements that apply to thedisposal of drill cuttings on the earth's surface that, based on goodscience, will permit or facilitate re-vegetation.

In the process for remediating contaminated drill cutting (or minetailings), the biocatalyst is activated by mixing it with a nutrient andwater, if needed, 20. The activated biocatalyst is introduced to thecontaminated drill cuttings, 22, typically in a drill cuttings box inwhich the contaminated material has been placed. Optionally, the drillcuttings are pretreated with the activated biocatalyst, 21, bycontacting the drill cuttings with the activated biocatalyst. In oneembodiment, the activated biocatalyst is sprayed onto the drill cuttingson a shaker, and the pretreated drill cuttings are transferred to acontainer for mixture with the activated biocatalyst in step 22 withouta dryer or centrifugation step (as is conventionally done with drillcuttings exiting a shaker). Activated biocatalyst from the shaker isreused in the process or is disposed of, drilling fluid from the shakeris recycled from the shaker to the rig, and the cuttings, now pretreatedwith activated biocatalyst, are transferred to a container for furthertreatment (e.g., the pretreated cuttings are used in step 22 by mixingthe pretreated contaminated material with activated biocatalyst). Wateris added to the activated biocatalyst and contaminated drill cuttings toform a mixture, which in this embodiment is a slurry, and the slurry ismixed, 24, incubated, 26, and tested for a property, such as pH, oxygencontent, viscosity and/or contaminant level, 28. The more detaileddiscussion above on each of these steps applies equally to thisexemplary embodiment.

The remediated drill cuttings are transferred to another container, suchas a treatment cell, 30, for further processing. In one embodiment, theremediated drill cuttings are combined with a second material to form acomposite useful for another purpose, 32. In one embodiment, the secondmaterial is a material suitable for use in a road structure. A typicalroad construction includes a sub-grade of supporting native rock, soil,sand, clay or other material onto which a base layer generallycomprising a depth of crushed gravel or aggregate is placed andcompacted to form the paved surface. The remediated drill cuttings arecombined with one or more of the materials used in construction of aroad, a road sub-grade or a base layer. In one embodiment, theremediated drill cuttings are combined with an aggregate comprised ofgravel, sand or crushed stone to form a composite that is used in aproduct, 34, for example, in a road, a driveway, a parking lot or asidewalk. In one embodiment, the product 34 is used to form a caliche orcrushed rock road or pad site, for example on county roads, leased landfor oil and gas exploration or for similar purposes, or other sites. Inother embodiments, the product 34 is used to make paver bricks, canalblocks, flood blocks or jetty-type blocks. The ratio of remediated drillcuttings to aggregate can vary, and in one embodiment is selected toachieve a residual contaminant level in the remediated drill cuttingsthat is less than a regulatory limit for the contaminant. The actualproportions of drill cuttings relative to aggregate may be determinedthrough assessment of the relative amounts of and properties of thecontaminants. In one embodiment, the drill cuttings are blended withaggregate in a ratio of between 5-50% remediated drill cuttings,remainder aggregate. The blending of drill cuttings with aggregate maybe achieved through use of appropriate mixing equipment includingreclaimers either at the initial processing site or at the roadconstruction site, aggregate quarry or an asphalt plant. In oneembodiment, the remediated drill cuttings in combination with the secondmaterial yield a contaminant level that is at or below an acceptablelevel, which is typically a contaminant level that satisfies aregulatory (state, local, federal) level. That is, the contaminant levelin the remediated drill cuttings prior to addition of the secondmaterial may be greater than the acceptable contaminant level, andaddition of the second material results in a product that has acontaminant level that is at or lower than a regulatory mandated levelfor use or discharge of that contaminant into the environment.

It will be appreciated that the embodiment of remediatinghydrocarbon-contaminated drill cuttings is merely exemplary, as theprocess is application to the remediation of contaminants in soil, minetailings, water, and other materials.

C. Contaminated Soil

Leaks and accidental spills of hydrocarbons and chemicals occurregularly during the exploration, production, refining, transport, andstorage of petroleum and petroleum products. Release of hydrocarbonsinto the environment whether accidentally or due to human activities isa main cause of water and soil pollution. Chemicals commonly involved insoil pollution (also referred to as soil contamination) are petroleumhydrocarbons, pesticides and lead and other heavy metals. Soilcontamination can also happen as a result of underground storage tanksrupturing or the leaching of waste from landfills. Mining, fertilizerapplication, oil and fuel dumping and a multitude of other environmentalissues can also cause pollution of the soil. One of the more commoncontaminants are hydrocarbon-based compounds, and typical examplesinclude soil associated with compounds from refineries, servicestations, where both heavy-fraction hydrocarbons and light-fractionhydrocarbons that are inadvertently discharged into soil. Light-fractionhydrocarbon contaminate compounds include gasoline and aromaticcompounds, and heavy-fraction hydrocarbon contaminate compounds includediesel and kerosene.

In one embodiment, a process for remediation of contaminated soil isprovided. With reference to FIG. 3, the process comprises activating thebiocatalyst by combining it with a nutrient and, if needed, water 40.The contaminated soil, which can be in situ or ex situ having beenpreviously transferred to a suitable container, is mixed with theactivated biocatalyst, 42. Water is added to the activated biocatalystand contaminated soil to form a mixture, and the mixture is mixed, 44,incubated, 46, and tested for a property, such as pH, oxygen content,viscosity and/or contaminant level, 48. The more detailed discussionabove on each of these steps applies equally to this exemplaryembodiment.

The remediated soil can then be reused, 50. Reuses include returning theremediated soil to its original site or to a different site.

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,permutations, additions and sub-combinations thereof. It is thereforeintended that the following appended claims and claims hereafterintroduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are within their truespirit and scope.

It is claimed:
 1. A method to remediate a contaminated material,comprising: activating a biocatalyst that digests hydrocarboncontaminants with a nutrient, to provide an activated biocatalyst;introducing in the presence of water the activated biocatalyst to acontaminated material to form a mixture; incubating the mixture for aperiod of time; determining a property of the mixture; and determining alevel of contaminant in the mixture.
 2. The method of claim 1, whereinactivating comprises activating for between 5-24 hours, or whereinactivating comprises activating until the nutrient is more than 50%consumed by the biocatalyst, or wherein activating comprises activatinguntil carbon dioxide level in effluent gas associated with thebiocatalyst and nutrient is above a threshold level.
 3. The method ofclaim 1, wherein activating comprises wherein activating comprisesactivating for between about 5 minutes to about 60 minutes.
 4. Themethod of claim 1, wherein determining a property of the mixturecomprises determining pH, determining oxygen content, determining pH andoxygen content or determining viscosity of the mixture.
 5. The method ofclaim 4, wherein the method further comprises adjusting pH, adjustingoxygen content or adjusting viscosity of the mixture.
 6. The method ofclaim 4, wherein a pH level of less than 3 or a pH level of greater than11 triggers adding an additional amount of water to the mixture.
 7. Themethod of claim 1, wherein during the period of incubation time themixture is mixed periodically.
 8. The method of claim 1, wherein theperiod of incubation time is from 6-8 hours.
 9. The method of claim 1,wherein determining a level of contaminant comprises testing for ahydrocarbon contaminant level.
 10. The method of claim 9, furthercomprising adding an additional amount of activated biocatalyst when acontaminant level is above a threshold amount, to form an adjustedmixture.
 11. The method of claim 10, further comprising mixing theadjusted mixture, incubating the adjusted mixture and testing theadjusted mixture for hydrocarbon contaminant level.
 12. The method ofclaim 1, wherein incubating is performed at ambient temperature.
 13. Themethod of claim 1, wherein activating further comprises activating thebiocatalyst in the presence of a surfactant.
 14. The method claim 1,wherein the nutrient is selected from the group consisting of a foodsource, a sugar and compounds that provides nitrogen, potassium, orphosphate.
 15. The method of claim 1, wherein the biocatalyst comprisesa material selected from the group consisting of bacterialmicroorganisms, intracellular enzymes, and extracellular enzymes. 16.The method of claim 1, wherein the contaminated material is selectedfrom the group consisting of drill cuttings, soil, mine tailings, watercontaminated with oil, and water contaminated with an organic solvent.17. The method of claim 16, wherein the contaminated material is drillcuttings and the mixture is a slurry.
 18. The method of claim 16,wherein the contaminated material is drill cuttings and the methodfurther comprises pretreating the drill cuttings with activatedbiocatalyst prior to said introducing.
 19. A method to remediate acontaminated material, comprising: providing a biocatalyst; instructingto activate the biocatalyst by incubation with a nutrient to provide anactivated biocatalyst; and instructing that the activated biocatalyst beadmixed with water and a contaminated material to remediate thecontaminated material.
 20. The method of claim 19, wherein instructingto activate comprises instructing to activate for between 5-24 hours, orwherein instructing to activate comprises instructing to activate untilthe nutrient is more than 50% consumed by the biocatalyst, or whereininstructing to activate comprises instructing to activate until carbondioxide level in effluent gas associated with the biocatalyst andnutrient is above a threshold level.
 21. The method of claim 19, whereinactivating comprises wherein activating comprises activating for betweenabout 5 minutes to about 60 minutes.
 22. The method of claim 19, whereininstructing that the activated biocatalyst be admixed with water and acontaminated material forms a mixture, and the method further comprisesinstructing to determine a property of the mixture wherein the propertyis selected from pH, oxygen content, and viscosity.
 23. The method ofclaim 22, wherein the method further comprises instructing that one ormore of pH, oxygen content or viscosity of the mixture be adjusted. 24.The method of claim 22, wherein instructing comprises informing that apH level of less than 3 or a pH level of greater than 11 triggers addingan additional amount of the water to the mixture.
 25. The method ofclaim 19, wherein instructing to activate the biocatalyst by incubationwith a nutrient comprises instructing to activate the biocatalyst byincubation with a nutrient for an incubation period during which mixingoccurs periodically.
 26. The method of claim 19, wherein the methodfurther comprises instructing to determine a level of contaminant. 27.The method of claim 26, further comprising instructing to add anadditional amount of activated biocatalyst when a contaminant level isabove a threshold amount, to form an adjusted mixture comprised of thecontaminated material, activated biocatalyst, additional amount ofactivated biocatalyst and contaminated material.
 28. The method of claim27, further comprising instructing to mix the adjusted mixture, toincubate the adjusted mixture and test the adjusted mixture forhydrocarbon contaminant level.
 29. A method to remediate and recycle acontaminated material, comprising: providing a biocatalyst and anutrient that when mixed form an activated biocatalyst; mixing theactivated biocatalyst with water and a contaminated material to form amixture; incubating the mixture for a period of time; testing themixture to ascertain contaminant level; and processing the mixture, whenits contaminant level is equal to or less than an acceptable level, toform a remediated material; and processing the remediated material witha second material to form a recycled product with a contaminant levelequal to or less than an applicable regulatory limit.
 30. The method ofclaim 29, wherein the second material is a material suitable for use asa flexible road base.
 31. The method of claim 30, wherein the materialsuitable for road construction is an aggregate comprised of gravel, sandor crushed stone.